Formation and segregation of primary silicon in Bridgman solidified Al-18.3 wt% Si alloy

Dong, Liang; Bayraktar, Y.; Jones, H.

doi:10.1016/0956-7151(94)00287-r

Cited by 39 publications

(26 citation statements)

References 16 publications

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“…For Al-Si alloys, rapid-solidification experiments of the kind previously outlined have been used to infer correlations between the morphology of the primary silicon and the melt undercooling. [7][8][9][10][11][12][14][15][16] But, direct studies of the role of undercooling have been hindered by the difficulty in attaining moderate to high undercoolings in bulk samples. In general, it has proved difficult to attain substantial undercoolings of aluminum alloys in electromagnetic levitation experiments.…”

Section: Introductionmentioning

confidence: 98%

“…[1,2,3] The alloys are eutectic, but, depending on composition, the microstructures can show primary ␣-Al dendrites or primary Si, and the eutectic itself can be fibrous or platelike. Dramatic microstructure modification can be achieved by adding elements such as Ti, P, Na, or Sr, [1][2][3][4][5][6][7] by directional solidification, [8][9][10][11][12][13] or by rapid cooling such as in surface treatment with high-energy beams. [14,15,16] Particular attention has been paid to the morphology of the primary and eutectic silicon phases.…”

Section: Introductionmentioning

confidence: 99%

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Undercooling and solidification of Al-50 at. pct Si Alloy by electromagnetic levitation

Liu

Herlach

Vandyoussefi

et al. 2004

Metall Mater Trans A

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Electromagnetic levitation is applied to achieve containerless solidification of 10-mm-diameter droplets of Al-50 at. pct Si. A maximum undercooling of 320 K is obtained. Phase morphologies on the droplet surfaces and on the deeply etched sections of the samples solidified at different undercoolings are examined by scanning electron microscopy. The primary silicon shows well-developed faceted dendrites at a small undercooling, but a fine granular form at a large undercooling. Stratified deposits of aluminum are found within the primary silicon plates, arising from solute pileup during growth. The microstructural refinement at a large undercooling has its origins in solute restriction of crystal growth and in fragmentation of the primary silicon dendrites. The form of the Al-Si eutectic is also found to be changed into an anomalous form at a large undercooling.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Undercooling and solidification of Al-50 at. pct Si Alloy by electromagnetic levitation

Liu

Herlach

Vandyoussefi

et al. 2004

Metall Mater Trans A

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“…A series of morphologies of primary silicon has been observed in hypereutectic Al-Si alloys: plate-shaped crystal of hexagonal form, octahedral equi-axed crystals, star-like crystals containing two to five radiating twin planes, and more or less spherical shapes, etc. [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Growth of octahedral primary silicon in cast hypereutectic Al–Si alloys

Wang

Liu

et al. 2006

Journal of Crystal Growth

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“…THE morphology of silicon crystals growing from a melt is of interest in situations ranging from casting of Al-Si alloys [1][2][3][4][5] to laser processing of silicon thin films. [6,7,8] In particular, the morphologies of the primary Si phase in Al-Si alloys, and the associated growth mechanisms, have long been studied [1,[9][10][11][12] in relation to improving the microstructure and properties of castings.…”

Section: Introductionmentioning

confidence: 99%

Morphologies of silicon crystals solidified on a chill plate

Liu

Herlach

Vandyoussefi

et al. 2004

Metall Mater Trans A

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Electromagnetically levitated liquid droplets of pure Si or a Si-Ge alloy were cooled to different temperatures and then dropped onto a chill plate of Cu. Droplet oscillations mark the solid/liquid interface during solidification and permit the different crystal morphologies of silicon to be observed on the quenched surface by scanning electron microscopy (SEM). A spherical morphology found on the quenched surface represents the initial stage of crystal growth. Further growth leads to octahedral crystals bounded by {111} faces near equilibrium and to other polyhedra or even faceted dendrites further from equilibrium. The spherical growth can be observed only when the initial melt undercooling is moderately high. The critical size at which spherical crystals start to develop dendritic growth is much bigger than that calculated from the Mullins and Sekerka model, and is bigger than the Coriell and Parker model when kinetic undercooling is taken into account.

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Formation and segregation of primary silicon in Bridgman solidified Al-18.3 wt% Si alloy

Cited by 39 publications

References 16 publications

Undercooling and solidification of Al-50 at. pct Si Alloy by electromagnetic levitation

Undercooling and solidification of Al-50 at. pct Si Alloy by electromagnetic levitation

Growth of octahedral primary silicon in cast hypereutectic Al–Si alloys

Morphologies of silicon crystals solidified on a chill plate

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